The record influx of Muslim refugees last year coincided with a sharp decline in the number of violent anti-Semitic incidents in major European countries, many of which bore the brunt of the refugee crisis.

The wave of so-called new anti-Semitism of recent years largely stemmed from anti-Israeli rather than racist beliefs, and had often been linked to the persistence of such attitudes among the growing Muslim population. Yet data from the 2015 report on global anti-Semitism, published on Wednesday by Tel Aviv University's Kantor Center for the Study of Contemporary European Jewry, clearly show that as the refugees started coming in by the tens of thousands per day starting about a year ago, Europe became a safer place to be Jewish.

A Safer Europe for Jews

Number of major violent anti-Semitic incidents
per 1,000 of core Jewish population

According to data collected by the Israeli demographer Sergio DellaPergola, France, the U.K. and Germany are the European countries with the biggest core Jewish population, defined as people who describe themselves as Jews. In France, the number of major violent anti-Semitic attacks dropped to 72 last year from 164 in 2014. The U.K. saw a similarly steep decrease, to 62 from 141. In Germany, there were 37 attacks, down from 76. Throughout Europe, anti-Jewish violence is at the lowest level in a decade.

These statistics cover the worst anti-Semitic incidents, such as the November stabbing of a Jewish religious school teacher in Marseilles by a youth wearing an Islamic State T-shirt. A number of them were perpetrated by Islamic radicals, but plenty of others were the handiwork of white, indigenous racists. Out of the 360 U.K. anti-Semitic incidents -- both violent and non-violent ones -- for which data about the offenders were available, 208 of the perpetrators were described as white and European. White racists, however, have found a new target as more than a million Muslim immigrants arrived, and the established Muslim communities also feel under attack, the Kantor Center noted:

"Attention has been diverted from the Jewish communities to the Muslim-Christian relations. In a growing number of cases Christians have attacked Muslim individuals, set immigrants centers on fire and violated cemeteries and even mosques."

Along with a general tightening of security after the Paris terror attacks last year, this shift to second place in line for unwanted attention has benefited European Jews.

Another trend that may be at work is the shift of xenophobic voters from fringe racist parties to more mainstream hard-right ones as what is perceived as a growing Islamist threat gains political traction. These political forces are often pro-Israel, Mikael Shainkman wrote in the Scandinavian part of the report, because they see Israel as their ally in a fight against the spread of Islam, though " historically, intolerant extremist parties have rarely kept away from attacking Jews in the long run."

Indeed, some extreme right-wingers see the refugee crisis as part of a Jewish plot to destroy European identity and subvert Christianity.

Despite the decrease in violent attacks, many European Jews don't feel safer. Sarah Rembiszewski wrote in the German part of the Kantor Center report that in Germany, which took in most of the newcomers, Jews have been "living in ever increasing fear, mainly of the unknown, related to the possible demographic changes due to the influx of a population with high antisemitic and anti-Israel potential." I have noticed this sentiment among the former Soviet Jews in Germany: Far from heaving a sigh of relief that racists have found new scapegoats, they have been talking about the growing danger of donning a kippah in neighborhoods with large Muslim populations.

Those fears may be justified only if the right-wing radicals are right about the growing Islamization of Europe. If the Muslim communities somehow gain ascendancy and the hard-core anti-Israel elements within them gain an upper hand, Jews may be in greater danger. It's more likely, however, that the relative calm of 2015 will endure: Muslims, themselves subjected to xenophobia, won't be aggressive toward other minorities, though the antipathy toward Israel will endure.

The Kantor Center subscribes to a broad definition of anti-Semitism -- the one the European Union used semi-officially beginning in 2005 but dropped in 2013. It includes anti-Israel, not just racist anti-Jewish manifestations. By those criteria, the growth of Europe's Muslim population may well contribute to the growth of anti-Semitism once the new immigrants settle and feel more comfortable expressing their old-country ideological preferences. That, however, won't necessarily translate into violence against Jewish neighbors. The behavior of the growing Muslim diasporas will test the validity of the broad definition of anti-Semitism. A practical distinction may need to be made between the hatred of Jews, which gives rise to violence against them, and the opposition to Israel's policies, which may well be limited to noisy rallies and social network polemics.

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.